My significant other occasionally raises a concern about faith; especially faith among people knew to the idea. She worries that it could be a fad, for them, that the fleeting red-hot-burn of fresh revelation cannot last, that early ultraorthodox super-piety must eventually self-consume and burn out. A simple idea at first blush, it is actually strikingly poignant.
If a new convert to any faith finds themselves flagging, they might begin to think they are losing faith, as well as piety. Often, the rituals become the important thing; the praying, or meditation, or fasting, or whatever other form of worship. Worship becomes an end, rather than a means, and stagnation eventually sets in. I, for one, can often become so consumed in the idea of "praying properly" that we forget why I am praying at all. Prayer is supposed to be a means, a method of moving closer to God as we understand Him.
Piety, in all its forms, is at once virtue and vice. It is important to keep the growth of the spirit, and of the understanding of God, as a priority for our lives. These are questions that must be answered, if only because no clear answers have ever or will ever exist. It isn`t something we can be taught, but a field of personal exploration, as important as coming to understand ourselves, our limits, and our behaviour. Piety can inspire us to pursue these needs of ours, but at the same time, it can lock us into a rigidity of thought and an adherence to doctrine.
Adherence to doctrine is, in itself, not a negative thing. It becomes a negative when this adherence is blind, lacking in purposeful examination from a critical mindset. This is what I would call over-piety; piety for its own sake, for the sake of the religion, rather than the sake of the faith.
We must remember that we are followers of God first, and the artifices of his worship favour.